The city is already trying to rein in rogue delivery cyclists — three months before strict regulations are scheduled to take effect.

The Department of Transportation’s new team of six inspectors has already visited 3,530 businesses that employ cyclists — such as restaurants and bodegas that offer deliveries — to warn them of the upcoming legal changes in April.

Inspectors found that 57 percent of the businesses were already putting up mandated informational cycling-safety posters that tell riders to stay off the sidewalk, yield to pedestrians and use bike lanes if they’re available.

The rules also require riders to wear helmets, a light- reflectimg shirt or vest, and an employee ID number next to the name of their employer’s business.

Once the rules kick in, anyone who sees a commercial cyclist flouting them can call 311 to report the business by using the ID number. Inspectors can dole out fines of up to $250 to any business in violation.